The Cruze diesel will get the same mileage as the Eco version but go longer between fuel stops? How is that possible? They're putting in a larger fuel tank as a marketing gimmick?

The trouble is they'll probably charge $1-2k for the diesel, and diesel fuel costs $.40 more than gas, and diesels cost more to maintain, all for what? Some more torque? If it doesn't significantly help acceleration it won't matter much. It'll be a poor value proposition for the masses.